and Structural Heart Disease
Pre-natal & Neonatal
The neonatal period is the time when many
congenital heart diseases manifest themselves, as it is the time when
the fetal circulation changes over to that of post-natal
circulation. Cyanosis, shortness of breath, or the need to stay in
the hospital for prolonged period may be indicators to cardiovascular
problems. On the other hand, because of normally elevated
pulmonary arterial vascular resistance in the neonatal period, the
pulmonary arterial pressure remains high. This may cause many left
to right shunting lesions, such ASD, BVSD and PDA to be silent due to
low velocity shunting.
Red Flags! What
to think of when encountering specific historical information?
d-TGA, VSD, Coarctation of the aorta
||AV Block, dilated
|Maternal Alcohol Abuse
||VSD, ASD, TOF, Coarctation
of the aorta
||PDA, PPS, VSD, ASD,
fibromuscular and intimal proliferation of medium and large
||40% have CHD, these include:
AVC, VSD, ASD, TOF, PDA, from most common to least common
of the aorta, bicuspid aortic valve, aortic dilatation, dissection
cases: PS, conduction abnormalities (SAD), ASD, VSD, TOF, sub
AS, complex CHD
Bluish discoloration of the skin or mucosa is termed cyanosis.
This is caused by an increase in the percentage of de-oxygenated
hemoglobin, which is blue in color. Increase in the level of
de-oxygenated hemoglobin could be because of central reasons such as
cyanotic congenital heart disease or lung disease rendering the blood
ejected out of the heart and into the aorta not fully oxygenated, i.e.
blue in color, causing bluish discoloration in the lips and nail beds as
well as the entire skin and mucosa. On the other hand, deprivation
of blood supply to a peripheral body part will cause peripheral cyanosis
(acrocyanosis). Peripheral cyanosis is seen in cases as in tourniquet
application to a limb, such as when the cuff of a blood pressure device
is inflated, or in case of vasoconstriction due to cold weather or poor
cardiac output. The blood entering through the arterial system to
the blood deprived limb is fully saturated and pink in color.
However, due to the limited blood supply, the tissues of that limb will
increase its oxygen extraction causing significant drop in the level of
oxygenated hemoglobin and an increase in de-oxygenated hemoglobin
resulting in cyanosis.
Shortness of Breath
Most congenital heart diseases are associated
with increase pulmonary blood flow. Whenever there is normal or near
normal pulmonary arterial anatomy together with a communication between
the systemic and pulmonary circulations, blood will shunt left to right
causing increase in pulmonary blood flow. The preference of blood to
shunt left to right rather than right to left whenever there is a septal
defect is because the pulmonary vascular resistance (about 3 Wood units)
is so much less than the systemic vascular resistance (25 Wood
units). This makes it easier for blood to go to the pulmonary
circulation rather than the systemic circulation.
Lungs with increased blood flow will have its vasculature engorged,
resulting in interstitial edema. The excess fluid in the lung
tissues will therefore act as a barrier for proper gaseous exchange,
rendering the process less effective. To compensate the respiratory
rate and effort increases manifesting as respiratory distress.
Easy Fatigability &
Failure to Thrive
respiratory distress and poor cardiac output due to heart disease cannot
feed well as it requires considerable effort to suckle resulting in easy
fatigability and failure to thrive.
consciousness may occur secondary to neurological or cardiac
reasons. Cardiac etiologies of syncope share the same outcome:
significant reduction of cardiac output. This may result through one
of the following mechanisms:
A heart rate that is too fast to allow for proper filling of ventricles
prior to contraction will cause reduced cardiac output. Also, a
heart rate too slow to generate adequate cardiac output will aslo result
Obstruction to blood flow:
Patients with severe hypertrophy of the ventricular septum resulting in
LVOT obstruction may develop syncope if the obstruction due to muscular
contraction becomes acutely more severe. also obstruction of the
right ventricular outflow tract, such as with TOF, may also cause acute
restriction of blood flow. In the latter example, this is
complicated by excessive and acute right to left shunting making the
reduced cardiac output significantly oxygen de-saturated.
A combination of reduced venous return and bradycardia causes drop in
cardiac output, resulting in syncope. See below for details.
Indicates abnormal heart rhythm which
may be too slow, too fast or just irregular. Children may complain
of chest pain when they are actually experiencing arrhythmias.
Chest pain is
rarely due to cardiac reasons in the pediatric age group. Myocardial
infarction may occur in children such as with
anomalous left coronary artery from pulmonary artery, coronary arterial
wall thickening in Williams syndrome, or Kawasaki disease. However,
in the majority of these cases chest pain is not verbalized.
Chest pain in most instances is due to non-cardiac reasons such as:
viral inflammation of the costochondral joints. Usually preceded by
a viral illness. There is reproducible pain when palpating costochondral
joints involved. Treat with anti-inflammatory agent, may
reoccur. Tends to occur more commonly in teenage girls.
Due to muscle strain such as with exercise, particularly weight
lifting. Characterized by worsening when using involved muscles.
due to inflammation
Skin disease: such as herpes
zoster, or other lesions.
cardiovascular examination in children one should follow the usual
sequence of assessment: inspection, palpation then auscultation.
Percussion has no significant role in pediatric cardiovascular assessment,
particularly in infants and young children.
general appearance of the baby or child should be assessed. The
examiner should ask him or herself the following:
Is the child too ill? Is there
significant respiratory distress? Is there cyanosis? Does the
child have syndromic features, such as Down's syndrome, etc?
Cyanosis is caused by an increase in the level of de-oxygenated hemoglobin
which has a blue color in contrast to oxygenated hemoglobin which has a pink
color. A level of 2 g/dl of de-oxygenated hemoglobin in the blood is
required before cyanosis is noticeable.
Scenario "1" is that of
a normal child. The level of de-oxygenated blood in arterial
circulation is too low to cause noticeable cyanosis. Scenario
"2" is that of cyanotic congenital heart disease. The
de-oxygenated hemoglobin level in the blood is high enough to cause
cyanosis. Scenario "3" is that of severe anemia and oxygen
saturation, but without noticeable cyanosis. The level of O2
desaturation (85%) is enough to normally cause cyanosis, however, due to the
anemia, the level of hemoglobin which would be desaturated is too low to
cause any significant bluish discoloration of the blood.
Unlike congestive heart failure in the adult population, edema is not a
common feature of CHF in children. When present it is best detected
over the sacral region, particularly in babies. Swelling of the head
and distended neck veins is noted in patients with Glenn shunt and increase
pulmonary vascular resistance.
Clubbing of the digits occurs because of hypoxia. Peripheral tissues
are most vulnerable to hypoxia, therefore with cyanosis and poor cardiac
output, the peripheral tissues get around the low oxygen supply by opening
many capillaries causing swelling of the digits. Clubbing is seen in
other lesions with low oxygen supply such as with lung diseases or diseases
causing chronic anemia, such as hepatic diseases and irritable bowel
Normally is 1-2 seconds in duration. Prolonged capillary refill time
indicates poor cardiac output. It should be noted thought, that a
brisk capillary refill is seen, despite poor cardiac output in cases where
the peripheral vasculature are forced to vasodilate such as with sepsis or
the use of pharmacologic agents.
Femoral an brachial arterial pulses should be
felt simultaneously to assess their strength and timing. In
coarctation of the aorta the femoral pulsation is weaker and delayed in
timing when compared to the brachial arterial pulse. It is important
when doing this assessment to use the right brachial arterial pulse, as the
left subclavian may be involved or distal in its origin tot he coarctation
and will therefore be as weak as the femoral arterial pulse.
Peripheral pulses also gives a sense of the
cardiac output, systolic and diastolic pressures. Poor cardiac output
results in low systolic and high diastolic blood pressure, hence a narrow
pulse pressure. On the other hand, a low diastolic BP, such as with
PDA or aortic regurgitation will cause a wide pulse pressure.
Normal pulse pressure
Narrow pulse pressure
Wide pulse pressure
and rarely hepato-spleenomegaly is seen in CHF due to elevated central
A palpable thrill over the precordium or
suprasternal notch indicates significant murmur. The RV impulse (left
lower sternal border) and LV (apical) impulse may indicate hypertrophy or
hypoplasia of that chamber.
Rarely crackles are heard in pulmonary edema since breathing sounds in
children is bronchial in nature and not alveolar as heard in
adults. Therefore, even significant edema may not cause audible
First heart sound (S1):
Closure of atrio-ventricular valves.
Second heart sound (S2):
A2: closure of aortic valve,
P2: closure of pulmonary valve
Single S2 = absent pulmonary or aortic component or delayed closure of
P2 superimposing A2
inaudible P2 due to TGA
Does the splitting of S2 vary with respiration?
Added sounds: Gallop rhythm: S3, S4
Are sounds caused by the turbulence of blood flow. Physiologic blood
flow is laminar and as such is smooth and noiseless. Turbulence of
blood flow results from abnormal blood flow from a high pressure
chamber/vessel to a lower pressure chamber/vessel. This may be due to
an abnormal communication (e.g. VSD), or narrowing of a passageway (e.g.
valve or artery stenosis), or increase in volume of blood flow (e.g. ASD,
Grades: 1-6, one being the softest and six being the loudest.
By definition grade four murmur is associated with a palpable thrill.
Definition: Murmur heard throughout systole, typically in a
plateau fashion. This typically extends throughout
systole and therefore, obscures S1 and S2.
Holosystolic murmur indicate shunting of blood between two structures
in which the pressure in one structure is higher than
the other throughout systole, example:
Soft: Atrio-ventricular valve regurgitation such as mitral regurgitation.
Tricuspid regurgitation is audible only with pulmonary (RV)
Ejection systolic murmur:
heard in systole, in a crescendo-decrescendo fashion. The murmur
is mid-systolic and is preceded by a click due to opening of an abnormal
(thickened) pulmonary or aortic valves. Ejection systolic murmurs
indicate shunting of blood
between two structures in which the pressure in one structure is higher
than the other in mid-systole, example:
Increase in blood flow turbulence as systole progresses due to an increasing amount of
blood flow through a restricted orifice, such as:
Definition: Murmur heard in systole, in a
crescendo-decrescendo fashion. The murmur is
mid-systolic and NOT associated with a click. Ejection
systolic murmurs indicate
shunting of blood between two structures in which the
pressure in one structure is higher than the other in mid-systole, example:
Increase volume of blood flowing through normal valves
ASD, this murmur is associated with a mid-diastolic murmur and fixed
splitting of second heart sound
Or small VSD,
which is not open throughout systole due to constricting
effecting of contracting myocardial fibers.
Early diastolic murmur:
Definition: Murmur heard in early diastole, in a decrescendo
fashion. The murmur immediately follows S2.
represents leakage of blood through aortic or pulmonary
valve (pulmonary regurgitation is heard only in association
with pulmonary hypertension).
|Systolic and diastolic murmur:
Definition: Murmur heard in systole and diastole, in a
continuous fashion. The murmur may obscure S1 and S2.
represents blood flow from a systemic artery to other
structures, such as:
Systemic artery to pulmonary artery: PDA, collateral
Systemic artery to vein: arteriovenous fistula
Systemic artery to right ventricle: coronary artery-RV
Soft continuous murmur over the
neck may represent venous hum, an innocent heart murmur.
Definition: Murmur heard in a continuous fashion, regardless
of cardiac cycle and may change in character in different
patient positions (supine, on side, sitting, etc.)